Besides the peaks at \(\pm \Delta /e\) , tunneling conductance shows additional in-gap features: double peaks at \(V_\text{DC}\)  considerably lower than \(\Delta /e\)  (\(\approx 7 \mu \)  V), and zero bias peaks close to pinch-off. This is reminiscent of the in-gap states observed in vertical LAO/STO tunnel junctions [1]}. Possible explanations involve two-band superconductivity with a small second gap [2]}, [3]}, suppression of the superconducting order parameter next to the tunneling barrier due to proximity effect [4]}, [5]}, Kondo effect [6]}, spontaneous Majorana or Andreev bound states [7]}, [1]}, [9]}. At the present stage, we do not attempt to discriminate between these possibilities.
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